Degasser



Jan. 28, 1941. R, HUFFQRD l y 2,229,851

DEGASSER Filed OC.. 5, 1939 BY @f/MJ# A ORNEY Patented Jan. 28, 1941 UNITED STATES PATENT OFFICE 4 Claims.

This invention relates to a fuel supply cutout device automatically operable by engine suction when the usual throttle or a governor valve is actuated to reduce the volume of fuel mixture supplied to the engine.

The chief object of this invention is to provide a construction which does not in any way interfere with the carburetor at any time except during the overrun or high vacuum period when it is operative in effect to cut off the flow of raw fuel to the carbureting means.

This application is a continuation-in-part of the copending application Serial No. 230,738, filed September 19, 1938, and entitled Degassen The chief feature of the device consists in providing means which prevents raw fuel flow to the carbureting means by closing the usual carburetor vent normally open to the atmosphere, which means is normally inoperative when the engine equipped therewith is running idle but which means becomes operative when the vehicle runs down hill or decelerates and operates the engine.

Another feature of the invention is that it is operable by intake suction, the invention being connected to the intake system between the throttle or governor valve and the engine or more especially the intake valves thereof, to-wit, downstream of the intake system valve control, whether the same be that of the carburetor throttle valve and/or of a governor valve ahead of or downstream of the carburetor structure.

The invention also is similarly operable in the event that a governor structure is built into a carburetor and the throttle valve thereof functions in the usual manner of a carburetor throttle and/or a governor throttle valve.

The full nature of the invention will be more fully understood by the accompanying drawing and the following description and claims.

In the drawing,

Fig. 1 is a diagrammatic illustration of a combined air cleaner and downdraft carburetor with the invention applied thereto, the major portion of the invention and a portion of the carburetor being illustrated in section for clearness.

Fig. 2 is a sectional view of a modified form of the major portion of the invention proper.'

Fig. 3 is a transverse sectional view taken on line 3 3 of Fig. 2 and in the direction of the arrows. I

In Fig. 1 of the drawing, It indicates a conventional air cleaner which is connected to a downdraft carburetor II having, for example, the usual throttle valve I2 therein and which is adapted, as is well known, for manual operation and control through a hand throttle, a foot throttle or both. This downdraft carburetor II includes a float bowl structure, indicated generally by the numeral I3. The mechanism in- 5 terior thereof is specifically omitted, since it may assume many forms well known in the carburetor industry.

Suiiice to say, in order to insure the flow of fuel from the oat chamber to the fuel feeding 10 mechanism, some provision must be made to vent said chamberto atmosphere or the equivalent so that the fuel does not vacuum lock in the oat chamber. Herein this vent is indicated by the numeral I4. It may be protected by a 15 screen filter, or the like, as desired or required. The present invention, therefore, is directly associated with this vent I4.

Herein the numeral I5 indicates a body portion provided with an elongated chamber I8 20 which constitutes a cylindrical extension in which is slidably mounted a piston structure II, the latter being chambered as at I8 to nest one end of a. spring I9, the other end being concentric with a stem or cylinder 20 carried by a 25 threaded member 2l having threaded connection with one end of the cylinder I6 and constituting a closure for that end of the cylinder. The exposed end of the member 2l is slotted as at 22 for screw driver or like engagement, permitting 'the adjustment of the member 2| for spring force adjustment. The member 2l is locked in adjusted position by the nut 23. The spring normally constrains the piston toward the left in Fig. 1. l 35 Herein integral with the piston is an extension 2B also slidable in the cylinder, last mentioned, and said extension is provided with an annular channel or groove 25. The opposite end of the cylinder is formed by the wall 26 slightly 40 remote from the extreme left hand end of the body portion I5. Adjacent said wall there is a borev and the same is threaded as at 21 to receive the threaded portion 28 of a conduit retainer or pipe connection 29. The reduced or wall portion 26 is apertured as at 3l! and thus is in free communication atV all times with the conduit 3l connected to the cylinder by the pipe connection 2S. Upstream of the throttle valve or throttle 5 valves, and in the intake system, in the present instance, is a port 32 providing communication to a duct 33. This duct isconnected and is in free communication with a conduit 34 connected as at 35 to a ported boss 3 .8 on the body I5. This 55 ported boss has the duct or port 31 therein which herein is shown in diametrical augment with the port I4, the latter communicating with the passage 33 in the body I5.. Passages 38 and 31 preferably constitute extensions of each other with the cylinder I3 included therebetween.

When the piston is positioned as shown in Fig. 1, the annular channel 25 permits free communication between the port 32 and the float chamber I3, thus insuring normal operation of the carburetor. It will also be observed and incident to the present arrangement, that the air which is supplied to relieve vacuum lock in the carburetor bowl chamber is clean air since it has been cleaned by the air-cleaner I0.

The conduit 3| previously described is suitably connected as at 40 to a boss 4I which boss is provided with a passage 42 therethrough opening as at 43 or ported to the intake IIA of the carburetor intake portion immediately adjacent and upstream of the throttle valve I2.

Another boss 44 is provided with passage 45 communicating by the port 48 with the intake passage portion IIB and. downstream of the throttle valve. A conduit 41 is connected by the pipe connection 4I to said boss 44 and communicates at its opposite end as at 49 to a passage 50 which leads to a communication with the cylinder I3 but rearwardly of the piston I1.

Having thus briefly described the simplest form of the invention. its operation may be similarly set forth as follows:

With the throttle valve I2 in wide open posi- .tion or in any intermediate position, such as indicated at I2' except when fully closed or substantially so as shown at I2", it will be noted that the intake suction is applied with equal degree through the ports 46 and 43 to the conduits 41 and 3|, respectively, whereupon suction pressures upon both sides ofthe valve are equalized and spring I9 holds the piston valve in open position or with the port or vent I4 in the carburetor bowl in communication with the air intake system of the engine. Under these circumstances liquid in the fuel bowl is free to flow to the mixing chamber. When the throttle valve I2 is moved to the dotted line closed position shown in Fig. 1 at I2", it will be apparent that high vacuum or downstream suction is applied at port 46 by way of conduit 41 to the recessed face of the piston valve while the pressure at port 43 is increased to approximately atmospheric. With redu ed pressure behind the slide valve and atmosp eric pressure ahead of the valve, the force of spring I9 is overcome and the valve is moved against such force rearwardly of the casing and vent I4 is out oiI and sealed.

In Fig. 2 or 3 numerals similar to those previously utilized but of the |00 series, are employed. In this form of the invention the forward end of the piston valve is suitably relieved as at lIGII and a pin |10 extends across the cylinder and serves as a piston and valve guide to prevent rotation of the same in the cylinder but permits the piston and valve to reciprocate as required.

There also is provided leading from the spring nesting face of the piston, a passage |10. This herein is shown coaxial with the piston and valve axis and communicates with a lateral passage or duct I1 I. It will be observed-see Fig. 2--that in theA normal engine operation this passage, et cetera, is ineffective. When, however, the throttle valve has been closed-or is, substantially closed-and high vacuum downstream of the valve is effective, the piston valve, as previously described, moves to the right to seal communication between passages |31. and |33 of this control mechanism and hence, vto seal the atmospheric vent I4see Fig. 1.

With the form of the invention shown in Figs. 2 and 3, this high vacuum or suction is now applied through the ports or passages |10 and I1I to the passage |38 so that in the event there is a leak, or there are structural leaks, in the carburetor bowl structure, this suction is imposed upon the carburetor bowl chamber and compensates or nulliiles the eiect of such leak, or leaks,

so that the vacuum lock is positively insured and this prevents wasteful flow of fuel to the intake of the engine. Also it will be noted that with this form of the invention, the vacuum lock is eiective at an earlier period than the vacuum lock becomes effective, with the form of the invention shown in Fig. 1, for this reason.

The vacuum lock with the device shown in Fig. 1 'is created by fuel flow alone, whereas in the form of the invention shown in Figs. 2 and 3, the vacuum lock is not only created by such fuel flow but is assisted or accelerated by the high vacuum incident to downstream suction upon closed throttle.

It is also to be noted that many carburetors are provided with the port 43-see Fig. l-for connection to a vacuum operable spark control device. In the event the carburetor is not soprovided, such a port may be made or the passage 30 in the cylinder head 25 may lead directly to atmosphere. It is also to be observed that in place of the connection 3| being direct between the invention and the port 43, it may be in an arrangement so that a branch is provided for a vacuum operable spark control. Furthermore, the line 41 instead of being a single line to the cylinder I6, may have a branch which leads to vacuum operable devices, such as a windshield wiper which must operate at all times' whether the engine be running under normal conditions or decelerating.

While the function of the degasser has been described in detail, it would be quite apparent to those skilled in the art that this structure can also be utilized for a maximum speed control independent of the calibration for degasser control. In such an instance, the valve could be worked from the water or oil pressure or by a vehicle momentum control set for any predetermined speed to air-lock the carburetor or fuel mixture device fuel bowl.

The invention claimed is:

1. In a carburetor including a fuel bowl having an atmospheric vent, a mixing chamber to receive fuel from said bowl and having a throttle valve therein, of a valve casing overlying said vent, a valve movable in said casing to control said vent and responsive to differential pressures at opposite ends of said casing, a spring normally holding said valve in vent-open position, suction pipes communicating with the opposite ends of said valve casing at one end and with the interior of said mixing chamber at their opposite ends and both arranged to be subjectto the reduced pressure in said chamber when the throttle valve is open, the pipe communicating with the vent-open end of said valve casing being in communication with said mixing chamber between the said throttle valve and atmosphere when the throttle valve is closed, and the pipe at the opposite end of said casing communicating with said mixing chamber downstream of said throttle valve.

2. In a carburetor including a fuel bowl having an atmospheric vent, a mixing chamber to receive fuel from said bowl and having a throttle valve therein, of a valve casing overlying said vent, a valve movable in said casing to control said vent and responsive to differential pressures at opposite ends of said casing, means yieldably holding said valve in vent-open position, a suction tube communicating at one end of said valve casing behind said valve and at its opposite end with the interior of said mixing chamber downstream of said throttle valve, and a second tube communicating at one end with said valve casing ahead of said valve and at its opposite end with said mixing chamber upstream of said throttle valve when the latter is in closed position, both of said tubes subject to the lreduced pressure in said mixing chamber when the throttle valve is open. g

3. In a carburetor, including a vfuel bowl having an atmospheric vent, a mixing chamber to receive uel from said bowl and having a throttle valve therein, of a valve casing overlying said vent, a valve movable in said casing to control said vent, said valve having a port adapted to register with said vent to open the latter to atmosphere when the valve is advanced to its limit of movement in one direction, said valve having a second port establishing communication between said fuel bowl and the space behind said valve when the latter is retracted, means yieldably holding said valve in vent-open position, a suction tube in communication at one end with the space behind said valve and at its oppositev end with said chamber downstream of said throttle valve, and a second tube in communication at one end with said valve casing ahead of said valve and at its opposite end with said mixing chamber upstream of said throttle valve where the latter is in closed position, both of said tubesV subject to the reduced pressure in said mixing chamber when the throttle valve is open.

4. In a carburetorl including a fuel bowl having an atmospheric vent, a mixing chamber to receive fuel from said bowl and having althrottle valve therein, a valve casing, a valve movable in said casing and adapted when in advanced position to establish communication between said vent and said fuel bowl and when retracted to establish communication between said fuel bowl and the space behind said valve, a spring normally holding said valve in advanced position, a suction pipe communicating at one end with the space behind said valve and at its opposite end with said mixing chamber downstream of said throttle valve, and a second pipe communicating at one end with the valve casing ahead of said valve and at its opposite end with said mixing chamber upstream of said throttle valve when the latter is in closed position, both of said pipes subject to the reduced pressure in said mixing chamber when the throttle valve is open.

RAYMOND HUF'FORD. v 

